Swivel Casters.

What are Swivel Casters?

Swivel casters, also known as swivel caster wheels or caster swivel wheels, are the steering half of Accu’s Casters & Wheels range, letting equipment change direction under load without being lifted or dragged. The wheel is carried in a fork that hangs beneath a swivel head, a bearing that lets the whole fork turn through a full 360 degrees beneath its fixing, with the axle set slightly behind the swivel’s center line. That offset lets the wheel follow whichever way the load is pushed, so a cart or machine base can be steered around corners, into tight bays and through doorways by hand.

Many of the swivel casters are classified under a European standard: EN 12530 covers institutional settings, EN 12532 industrial equipment moved at up to 4 km/h and EN 12533 industrial equipment moved at 4 km/h to 16 km/h. They are used on almost anything that has to be moved and positioned by hand, from carts, platform trucks and mobile workbenches to laboratory apparatus, production equipment, machine bases and heavy transport frames.

How Swivel Casters Work

A swivel caster fixes to the underside of the equipment through a top plate, a single bolt hole or a threaded stem, and the swivel head above the fork turns on a ball raceway or a precision ball bearing. The wheel’s axle sits a set distance behind the swivel axis, known as the swivel offset, which runs from 18 mm to 60 mm across the range. When the equipment moves, that offset turns the fork so the wheel trails behind its pivot and lines up with the direction of travel, the same self-aligning action seen on a shopping cart. The radius of the circle the caster sweeps as it turns is the swivel radius, from 37 mm to 190 mm, and that space needs to stay clear of the frame and of neighboring casters.

Picture a platform truck in a distribution center, carrying up to 600 kg of boxed goods on a 90 kg frame, steered by a swivel pair at the handle end and kept on line by a fixed pair at the front. Spread over three casters, the usual allowance for an uneven floor, the load works out at 230 kg each, within the 250 kg rating of a 125 mm caster whose non-marking elastic rubber tread also protects the sealed warehouse floor. That caster has a swivel radius of 102.5 mm, so each one needs that much clearance around its pivot to spin freely without the fork striking the deck edge or the caster beside it. Without steering at the handle end, the operator would have to drag the truck sideways to turn into each aisle, scuffing the floor and fighting the load.

Materials Swivel Casters Are Made From

In Accu’s swivel caster wheels and housings, engineering-grade metals take the load through the swivel head while the polymer or elastomer tread is matched to the floor and the environment:

• Steel: Pressed steel housings and swivel heads in light to extra-heavy-duty grades, zinc plated against corrosion, many with a blue passivated finish.
• Stainless Steel: Swivel housings that stand up to repeated washdown, with the ALPHA STAINLESS casters scoring Excellent (5 of 5) for corrosion resistance.
• Cast Iron: KAPPA swivel housings in cast and forged iron, turning on double-row ball raceways or a tapered roller bearing and rated up to 1440 kg.
• Aluminium: A rigid, low-weight center for polyurethane and elastic rubber treads, keeping the wheel easy to turn as the caster swivels.
• Rubber: Cushioning treads in solid and elastic rubber, from non-marking compounds for finished floors to a heat-resistant version rated up to 250 °C.
• Rubber - TPR: An 87 Shore A thermoplastic rubber, used on twin-wheel and polyamide-housed swivel casters rated up to 100 kg.
• Plastic - PUR: Injection molded and cast polyurethane at 40 to 42 Shore D, which turns quietly under load and resists wear on busy swivel casters.
• Plastic - Nylon: Hard polyamide that swivels and rolls with little effort on smooth floors, used for wheels, wheel centers and the silver gray LEVINA housings.
• Plastic - PP: Light polypropylene, molded as solid wheels for small swivel casters and as centers for rubber and polyurethane treads.
• Plastic - Phenolic: A hard, rigid black wheel, including heat-resistant thermoset versions on stainless steel casters rated up to 280 °C.
• Plastic - TP: Fitted to two stainless steel swivel casters, a black thermoplastic wheel rated at 101.8 kg or 152.9 kg.

Sizes & Types of Swivel Casters Available

Swivel casters in Accu’s range run from compact sizes for light apparatus to heavy transport units, with the following wheel sizes, fixings and ratings:

• Wheel Diameter (D): 38 mm to 200 mm.
• Wheel Width (T): 16 mm to 50 mm.
• Mounting Height (H): 50 mm to 250 mm.
• Approximate Load Capacity: 25 kg to 1440 kg.
• Braked/Unbraked: Braked or Unbraked.
• Fixing Type: Bolt Hole Fixing; Rectangular Plate; Square Plate, 60 x 60 mm; Rectangular Plate, EN R42, 105 x 85 mm; Rectangular Plate, EN R43, 137 x 105 mm.
• Plate Fixing Hole Centres (ExG): 33 x 33 mm to 105 x 80 mm, plus 36 x 28 mm on the 38 mm compact caster.
• Fixing Hole Diameter: 5.3 mm to 11 mm.
• Bolt Hole Diameter: 11 mm or 13 mm.
• Thread Size: M10 x 25 to M12 x 30.
• Swivel Offset: 18 mm to 60 mm.
• Swivel Radius: 37 mm to 190 mm.

Not every fixing covers the full range. Threaded stem casters run from 40 mm to 100 mm wheels, carry up to 120 kg and come with zinc plated housings only, while bolt hole casters cover 50 mm to 125 mm wheels and loads up to 200 kg. Above 200 kg, every caster fixes through a top plate, and heavy-duty swivel casters rated at 500 kg or more all use the EN R43 plate. Swivel offset and swivel radius are listed in the tech spec where available and are worth checking before installing casters close to a frame edge. Braked versions are also listed under Casters With Brakes and are commonly paired with casters from the Fixed Casters range.

For loads that need to move in any direction across a fixed surface, such as conveyor tables and assembly benches, why not browse Accu’s Mini Ball Transfers and Long Life Heavy Duty Ball Transfers instead, which let the load roll over them in every direction.

FAQ

Q: What is a swivel caster?

A: A swivel caster is a wheel mounted in a fork that can rotate through a full 360 degrees beneath its fixing, so the equipment it carries can be steered in any direction. The axle is set slightly behind the swivel axis, so the wheel automatically trails into line with the direction of travel. In Accu’s range they fix with a top plate, a bolt hole or a threaded stem and carry from 25 kg to 1440 kg each.

Q: Do swivel casters go on the front or back?

A: On a cart that is pushed from one end, the swivel casters usually go at the handle end with fixed casters at the far end, so the operator steers from where they push while the fixed pair keeps the cart tracking straight. Equipment that is pulled or towed is often set up the other way around, with the swivels leading. Where equipment has to turn in place in a tight space, four swivel casters give the greatest maneuverability, usually with at least two braked so it can be held in position.

Q: What is the difference between swivel casters and fixed casters?

A: A swivel caster’s fork rotates through 360 degrees so it can steer, while a fixed caster’s fork is locked in one direction so it only rolls forward and backward. One makes equipment maneuverable while the other keeps it tracking straight and stops it from drifting sideways, which is why the two are so often combined on the same cart. Fixed casters also have no swivel radius to allow for, so they need less clearance under the frame.

Q: What are the two main types of casters?

A: By movement, the two main types are swivel casters and fixed casters, which are also called rigid casters. By mounting, casters either fix through a top plate bolted to the underside of the equipment or through a single point, such as a threaded stem or a bolt hole, which suits narrow legs and tubular frames. Accu’s swivel range is available with all three fixings, although plate fixing is the choice for heavier loads, and every caster in it rated above 200 kg uses a top plate.

Bespoke Swivel Casters Manufacture.

High precision, bespoke manufacture of Swivel Casters to customer specification. State of the art facilities specializing in both small batch prototyping and large scale manufacture.